Architectures/ARM/Fedora15 HardFP Bootstrap Virtual FAD 20110610

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[ARM] Fedora15 HardFP Bootstrap Virtual FAD - 2011/06/10

We wish to accelerate the bringup of Fedora 15 on ARMv7 systems running with hardware floating point (hardfp). To that end, it is proposed to have semi-regular bootstrap days, during which we will meet in a virtual capacity (on IRC, and over the phone) to build up through cross-compilation (and other means) the core packages required for Fedora 15 to become self-hosting on ARMv7 with hardware floating point.

When and Where

14:00 UTC, Friday June 10th 2011

IRC: #fedora-arm on irc.freenode.net

Phone: We used a temporary bridge

Etherpad: http://www.tinyurl.com/fedora-arm (including full list of international dialin numbers)

Event owners

• Jon Masters
• Chris Tyler

Attendees

• Jon Masters
• Chris Tyler
• DJ
• Anthony Boccia
• Salman Zafar
• Jon Chiappetta
• Paul Whalen
• Dennis Gilmore
• Brendan Conoboy
• Russ Herrold
• Peter Robinson

Summary

NOTE: Procedure for joining in with this post-activity day is documented on Architectures/ARM/Fedora15 HardFP Bootstrap

• We kicked off with a discussion around build flags and confirmed the current plans
  • Building with a Cortex-A8 optimized, hardfp target (aapcs, vfpv3-d16), no NEON, no Thumb2
  • We may rebuild with different core optimizations in the future, may enable Thumb2
  • Probably will not worry about NEON initially
• We reviewed various build dependencies we had available
  • Determined that tools for graphing and obtaining this stuff need improving
  • DJ provided an updated depsolving tool later in the day that was helpful
  • An initial attempt at a list of dependencies for RPM is in Etherpad
  • Determined we want to bring up rpm (rpm-build) at this stage
• We determined a workflow based around a rootfs image in git
  • http://git.fedorahosted.org/git/arm.git (ssh://git.fedorahosted.org/git/arm.git) - see the "armv7hl" branch on that repo
  • Based on DJ's git://fedorapeople.org/~djdelorie/bootstrap.git (output from a run of stage1/stage used as seed)
  • Individual people/groups to create branches named armv7hl-NAME and request merge on list (Jon Masters maintaining)
  • Each person/group picks a package at a time to bootstrap (edit the Etherpad to add your package status before/during/after - including changing the list of remaining packages/done packages)
  • Collaboratively edit stage2/stage2 (copy of version in bootstrap, to be synced back later)
  • Explode out new package rpmbuild bits into stage2/rpmbuild before/after adding rule to stage2/stage2
  • Packages build in stage2/builds and are installed to the git repo rootfs under a chroot
  • Mount this rootfs git repo and chroot on target, run /stage2/stage2 TARGET (where TARGET is e.g. "db4", "readline", etc.)
  • Ensure general rules are present in stage2 script in the "go" sections to call targets in order
  • Later will verify the bootstrap scripts still run, but use this rootfs git approach to speed up bootstrap
  • Contribution will continue to this repo - post pull requests/push to armv7hl-NAME branch
• We added more than a dozen bootstrap packages but more importantly worked out a workflow/model going forward
• Continue this effort and repeat the activity day.
• PROPOSAL: Next activity day on Wednesday June 22.

Program

• Summarize requirements/sync up on build flags
  • Build for Cortex A-8, with AAPCS, and hard float (vfpv3-d16, not -d32)
  • Do not enable NEON (can add later)
  • Do not enable Thumb2 (confirmed can non-disruptively enable per-package later)
• Current status of works in progress (DJ/Dennis/Seneca(?)?)
  • Plan will be to use DJ's bootstrap.git as a starting point
  • Extend stage2 script to on-target build up dependencies for rpm-build
  • Stash archives of populated build directories/bits on scotland.proximity.on.ca/fedora-arm/f15hardfp/bootstrap/
• Minimal dependency discussion for F15
  • Plan to build dependencies required from the dependency graph
  • F15 x86_64 rpm-build dependency graph generated from Koji build dependencies
• Plan for building/co-ordinating builds
  • Follow instructions for setting up DJ's bootstrap script and minimal rootfs (target chroot)
  • Grab a few package dependencies and work on them (add support to stage2 script)
  • Tar up the resulting build tree and make them available to others
  • Others install build tree ("make install") on their rootfs
  • Once sufficient deps are done for rpm, rebuild things as RPMs
  • host bits on scotland.proximity.on.ca/fedora-arm/f15hardfp/bootstrap/
  • Stage a Koji F15 instance with the working RPMs
• Status before end of day
• Plan for followup

Requirements

• Internet connection to log into IRC, and phone if possible (phone not essential)
• A supported ARMv7 target board
• Lots of coffee

Setup

• A pre-requisite is a working ARMv7-compatible supported target board, such as a BeagleBoard or a PandaBoard.
  • You can find out more from the main Fedora ARM pages about obtaining a pre-built rootfs (no installer yet)
  • We now have some Fedora ARM kernel packages for OMAP-based boards

• Bootstrap will involve using a partially completed rootfs image that will be used inside a chroot
  • Since the new "arch" (armv7hl) is supported by ARMv7 kernels we can use a chroot trick
  • A complete from-scratch new arch port would need an also bootable rootfs (but it's not quite that)
  • Your normal target rootfs will be the stock F-13 rootfs in this case (so boot target as normal, then use chroot)
• Fetch DJ's bootstrap.git repository
  • You will be making changes to the stage2 script (a copy of it in your rootfs)
  • Post patches and pull requests during the day for new packages
• Fetch the partially bootstrapped rootfs (progress to date, built using bootstrap scripts)
• Extract the root filesystem into a new directory and copy over to your board
  • Or mount over NFS from a server system (e.g. export /data/work/arm/bootstrap/f15/20110610/rootfs from a server to your board)
  • Optionally bind mount a directory within the rootfs (e.g. on an NFS server mount -o bind /data/work /data/work/arm/bootstrap/f15/20110610/rootfs/data/work) to allow you to get at data outside the chroot if you want to stash builds somewhere
• Chroot into the new target rootfs
  • chroot /data/work/arm/bootstrap/f15/20110610/rootfs (or wherever you extracted it)
• Take a look at the /stage2/stage2 script
  • Run it with a "module" name to build a particular package
  • /stage2/stage2 nspr
• Modify the stage2 script to support building additional packages in the target rootfs
• Post patches and git pull requests to the Fedora ARM mailing list (arm@lists.fedoraproject.org) (the stage2 script is kept in the bootstrap.git and a copy is in the rootfs)
• Once sufficient packages are bootstrapped to support rpm, rebuild packages using RPM
• Further dialog on package build deps and next steps